Design indicator for assessing proper sound insulation

Professional Definition

This is the value of acoustic insulation taken for design calculations, which includes a margin of safety in relation to the values obtained under laboratory conditions. In engineering practice, to obtain the design indicator of proper acoustic insulation (often denoted as R), a correction (usually 2 dB) is subtracted from the laboratory value to account for execution inaccuracies and differences between ideal conditions and real ones.

“This value serves as the basis for selecting building partitions, ensuring that after considering lateral transmission, the final acoustic insulation in the building meets the regulatory requirements.”

Acoustics in Simple Words

Imagine that a car manufacturer states fuel consumption at 5 liters per 100 km. This is the result achieved on a test track, under ideal weather conditions and with an empty tank (the equivalent of a laboratory indicator). However, when planning the budget for a holiday trip with the whole family and luggage, you assume a consumption of 7 liters (this is the design indicator). You do this to ensure you don’t run out of fuel halfway. In acoustics, we do the same – we assume that the wall on the construction site will "perform" slightly worse than in the laboratory because the mason may inaccurately apply the mortar, and the plaster may have microcracks.

Summary

The design indicator of insulation evaluation is a real value, adjusted for execution errors, that is used in acoustic simulations. It is a key tool to prevent situations where a building "on paper" meets standards, but in reality does not provide privacy.